Review
Overview of tools for the measurement of the orbital volume and their applications to orbital surgery

https://doi.org/10.1016/j.bjps.2020.08.101Get rights and content

Abstract

There are numerous applications in craniofacial surgery with orbital volume (OV) modification. The careful management of the OV is fundamental to obtain good esthetic and functional results in orbital surgery. With the growth of computer-aided design – computer-aided manufacturing (CAD-CAM) technologies, patient-specific implants and custom-made reconstruction are being used increasingly. The precise measurement of the OV before surgery is becoming a necessity for craniofacial surgeons. There is no consensus on orbital volume measurements (OVMs). Manual segmentation of computed tomography (CT) images is the most used method to determine the OV, but it is time-consuming and very sensitive to operator errors. Here, we describe the various methods of orbital volumetry validated in the literature that can be used by surgeons in preoperative planning of orbital surgery. We also describe the leading software employed for these methods and discuss clinical use (posttraumatic enophthalmos prediction and orbital reconstruction) in which OVMs are important.

Introduction

Orbital volume measurements (OVMs) are invaluable tools for surgeons. There are numerous clinical applications in craniofacial surgery with orbital volume (OV) modification: posttraumatic enophthalmos correction, orbital reconstruction, or orbital decompression following thyroid-related orbitopathy. All of these surgical procedures can alter the position of the ocular globe within the orbit.1 Computed tomography (CT) with multi-planar reconstruction is the reference imaging procedure for the assessment of craniofacial injuries because it provides the best spatial resolution and analysis of osseous structures.2

For decades, physicians have been measuring orbital structures in search of the predictive factors of enophthalmos after orbital fractures.3 It is well known that an increase of 1 cm3 in the OV is responsible for enophthalmos of 1 mm.4, 5, 6 Enophthalmos is considered to be clinically visible if it is > 2 mm.7 The careful management of the OV is, therefore, fundamental to obtain good esthetic and functional results in orbital reconstruction surgery. However, surgical indications are often selected based on the surgeon's personal experience without measurements on CT.2 This approximation frequently involves globe malpositioning postoperatively.

With the development of computer-aided design – computer-aided manufacturing (CAD-CAM) technologies, patient-specific implants and custom-made reconstructions are being used increasingly.8 It is becoming a necessity for craniofacial/orbital surgeons to measure the preoperative OV precisely to perform the best anatomic reconstruction of the orbit.

Currently, a consensus on OVMs is lacking. The manual segmentation of CT images is considered to be the “gold standard” to determine the OV. However, this method is time-consuming and very sensitive to operator errors.9 Semiautomatic and automatic methods are available for OV analyses, but have their own strengths and weaknesses. The main problem related to OVMs is the delimitation of orbital boundaries. Conversely, surgeons need a reliable, reproducible, easy-to-use, rapid and ideally free access OVM method for everyday use.

The aim of this overview is, therefore, to present the various methods of orbital volumetry validated in the literature that can be used currently by surgeons in the preoperative planning of orbital surgery.

Section snippets

Orbital volume measurements: historical background

For more than one century, scientists have been trying to develop a quantification method for the OV. The first OVMs were undertaken in the nineteenth century for anthropological and anatomic purposes. As medical knowledge progressed, the analysis of OV has proven to be very useful in the study and the treatment of traumatic, malformative, neoplastic, endocrine, or vascular disorders affecting orbital growth.10

In 1873 in France, Gayat was probably the first to publish OV data.11 He filled the

Main software of orbital volume measurement

The different methods of orbital volumetry described in the literature are listed below and summarized in Table 1.

Discussion

Different methods of OVM are validated, but there is no consensus on any of them. There are different clinical applications where the knowledge of OV can be very useful.

Conclusion

OVMs are becoming necessities in the era of virtual surgical planning and patient-specific orbital reconstruction and implants. OVMs are also useful for the prediction of posttraumatic enophthalmos.

Several methods and software types have been developed to measure the OV. Planimetry remains the most used technique, but various semiautomatic and automatic methods of OVMs are emerging from imaging software, which will probably, as their accuracy increases, become essential.

Declaration of Competing Interest

Authors have no conflict of interest to declare.

Funding

None.

Ethical approval

Not applicable.

References (54)

  • R.M. Zimmerer et al.

    A prospective multicenter study to compare the precision of posttraumatic internal orbital reconstruction with standard preformed and individualized orbital implants

    J Cranio Maxillo Fac Surg Off Publ Eur Assoc Cranio Maxillo Fac Surg

    (2016)
  • P. Scolozzi

    Applications of 3D orbital computer-assisted surgery (CAS)

    J Stomatol Oral Maxillofac Surg

    (2017)
  • M. Rana et al.

    Increasing the accuracy of orbital reconstruction with selective laser-melted patient-specific implants combined with intraoperative navigation

    J Oral Maxillofac Surg

    (2015)
  • Y.C. Kim et al.

    Patient-specific puzzle implant preformed with 3D-printed rapid prototype model for combined orbital floor and medial wall fracture

    J Plast Reconstr Aesthet Surg

    (2018)
  • D. Sozzi et al.

    Assessing the precision of posttraumatic orbital reconstruction through “mirror” orbital superimposition: a novel approach for testing the anatomical accuracy

    J Cranio Maxillofac Surg

    (2018)
  • T. Gander et al.

    Patient specific implants (PSI) in reconstruction of orbital floor and wall fractures

    J Cranio Maxillofac Surg

    (2015)
  • R. Zieliński et al.

    Classical versus custom orbital wall reconstruction: selected factors regarding surgery and hospitalization

    J Cranio Maxillo Fac Surg Off Publ Eur Assoc Cranio Maxillo Fac Surg

    (2017)
  • G. Bontzos et al.

    Ex vivo orbital volumetry using stereology and CT imaging: a comparison with manual planimetry

    Eur Radiol

    (2018)
  • G. Ramieri et al.

    Dimensions and volumes of the orbit and orbital fat in posttraumatic enophthalmos

    Dentomaxillofacial Radiol

    (2000)
  • R.W. Whitehouse et al.

    Prediction of enophthalmos by computed tomography after “blow out” orbital fracture

    Br J Ophthalmol

    (1994)
  • U. Bite et al.

    Orbital volume measurements in enophthalmos using three-dimensional CT imaging

    Plast Reconstr Surg

    (1985)
  • H.B. Ahn et al.

    Prediction of enophthalmos by computer-based volume measurement of orbital fractures in a Korean population

    Ophthal Plast Reconstr Surg

    (2008)
  • J.D. Osguthorpe

    Orbital wall fractures: evaluation and management

    Otolaryngol Neck Surg

    (1991)
  • J. Jansen et al.

    Orbital volume analysis: validation of a semi-automatic software segmentation method

    Int J Comput Assist Radiol Surg

    (2016)
  • W.C. Cooper

    A method for volume determination of the orbit and its contents by high resolution axial tomography and quantitative digital image analysis

    Trans Am Ophthalmol Soc

    (1985)
  • T.H. Osaki et al.

    Comparison of methodologies in volumetric orbitometry

    Ophthal Plast Reconstr Surg

    (2013)
  • T.H. P'an

    Measurement of the Chinese orbit

    J Anat

    (1933)

    • Cited by (23)

    • Reconstructive Surgery

      2023, Journal of Oral and Maxillofacial Surgery

    • Post-traumatic enophthalmos: Is it only about bone?

      2023, Journal of Stomatology, Oral and Maxillofacial Surgery

    • Morphometric and volumetric evaluations of orbit using three-dimensional computed tomography in southwestern Iranian population

      2023, Translational Research in Anatomy

    • 4D printed orbital stent for the treatment of enophthalmic invagination

      2022, Biomaterials
      Citation Excerpt :

      Second, the development of implants on CT directly affects the evaluation of postoperative surgical results. Based on the CT technique, clinical enophthalmos can be evaluated using orbital volume measurements (OVMs) [21,22]. Implants without CT development, such as Medpor and absorbable plates, are difficult to evaluate clinically [23].

    • Radiographic volumetric risk factors for late enophthalmos prediction in orbital blow-out fractures: A retrospective study

      2022, Journal of Cranio-Maxillofacial Surgery
      Citation Excerpt :

      Planimetry is currently considered as the gold standard (Kim et al., 2019). Nevertheless, it is very time-consuming and difficult to apply in clinical practice because it requires a slice-by-slice measurement (Sentucq et al., 2021). OV has been the first parameter described; it is known that its increase leads to enophthalmos appearance (Whitehouse et al., 1994; Fan et al., 2003; Sugiura et al., 2017; Schlund et al., 2020).

    • Reconstruction of Sphenoid Wing Dysplasia in Neurofibromatosis Type-1 Patients: An Evolving Technique

      2022, JPRAS Open
      Citation Excerpt :

      Measurement of orbital volume would be useful to monitor the progression of sphenoid wing dysplasia and provide assessment of pre- and postoperative changes. However, there is still no accepted gold standard for measuring the orbital volume, and therefore, it has not been adopted into our practice.8 Targeted medical strategies have the potential to dramatically alter the treatment landscape in NF-1 by reducing the volume of disease prior to surgery or eliminating the need for surgery entirely.

    View all citing articles on Scopus
    View full text
    © 2020 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.